This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A137622 #5 Mar 30 2012 18:50:59 %S A137622 1,2,4,3,8,5,11,6,7,9,18,10,22,12,13,14,29,15,33,16,17,19,40,20,21,23, %T A137622 24,25,51,26,54,27,28,30,31,32,64,34,35,36,72,37,76,38,39,41,84,42,43, %U A137622 44,45,46,94,47,48,49,50,52,104,53,109,55,56,57,58,59,120,60,61,62,127 %N A137622 Inverse of A137621. %H A137622 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %K A137622 nonn %O A137622 1,2 %A A137622 _Reinhard Zumkeller_, Jan 30 2008